Miliya T.Soputhy C.Leab P.Tan P.Sao S.Heffelfinger J.D.Batmunkh N.Ork V.Hossain M.S.Day N.P.J.Turner C.Turner P.Mahidol University2023-06-202023-06-202023-09-01IJID Regions Vol.8 (2023) , 9-15https://repository.li.mahidol.ac.th/handle/20.500.14594/87142Objectives: This study sought to characterize pneumococcal colonization and clinical/radiological features in Cambodian children admitted to hospital with an illness compatible with pneumonia following national introduction of the 13-valent pneumococcal conjugate vaccine (PCV13). Methods: Children aged 0–59 months admitted to Angkor Hospital for Children who met the World Health Organization (WHO) case definition for clinical pneumonia were enrolled over a 3-year period. Clinical, radiological and vaccination data were collected at enrolment. A nasopharyngeal swab was collected for detection of pneumococcal colonization using the WHO standard culture method. Results: Between 1 September 2015 and 31August 2018, 2209 analysable illness episodes were enrolled. Pneumococci were detected in 943/2209 (42.7%) children. PCV13 serotypes were detected less frequently in children who had been vaccinated appropriately for their age compared with undervaccinated children: 309/567 (53.6%) vs 216/342 (63.2%) (P=0.006). Age-appropriate PCV13 vaccination was negatively associated with hypoxic presentation [adjusted odds ratio (aOR) 0.72, 95% confidence interval (CI) 0.60–0.87; P=0.0006] and primary endpoint pneumonia on chest x ray (aOR 0.69, 95% CI 0.54–0.90; P=0.006). Conclusions: The introduction of PCV13 in Cambodia was associated with a decline in vaccine serotype nasopharyngeal colonization, and clinical and radiological severity in children hospitalized with clinical pneumonia.MedicineArticleSCOPUS10.1016/j.ijregi.2023.05.0052-s2.0-8516154314827727076